item service: always use last known price, and queue price updates instead

http-service/src/main/java/net/runelite/http/service/SpringBootWebApplication.java

@@ -44,11 +44,13 @@ import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.boot.builder.SpringApplicationBuilder;
 import org.springframework.boot.web.support.SpringBootServletInitializer;
 import org.springframework.context.annotation.Bean;
+import org.springframework.scheduling.annotation.EnableScheduling;
 import org.sql2o.Sql2o;
 import org.sql2o.converters.Converter;
 import org.sql2o.quirks.NoQuirks;
 
 @SpringBootApplication
+@EnableScheduling
 @Slf4j
 public class SpringBootWebApplication extends SpringBootServletInitializer
 {

http-service/src/main/java/net/runelite/http/service/item/ItemController.java

@@ -176,25 +176,30 @@ public class ItemController
 					.build();
 			}
 		}
+		else if (priceEntry == null)
+		{
+			// Price is unknown
+			List<PriceEntry> prices = itemService.fetchPrice(itemId);
+
+			if (prices == null || prices.isEmpty())
+			{
+				cachedEmpty.put(itemId, itemId);
+				return ResponseEntity.notFound()
+					.header(RUNELITE_CACHE, "MISS")
+					.build();
+			}
+
+			// Get the most recent price
+			priceEntry = prices.get(prices.size() - 1);
+			hit = false;
+		}
 		else
 		{
 			Instant cacheTime = now.minus(CACHE_DUATION);
-			if (priceEntry == null || priceEntry.getFetched_time().isBefore(cacheTime))
+			if (priceEntry.getFetched_time().isBefore(cacheTime))
 			{
-				// Price is unknown, or was fetched too long ago
-				List<PriceEntry> prices = itemService.fetchPrice(itemId);
-
-				if (prices == null || prices.isEmpty())
-				{
-					cachedEmpty.put(itemId, itemId);
-					return ResponseEntity.notFound()
-						.header(RUNELITE_CACHE, "MISS")
-						.build();
-				}
-
-				// Get the most recent price
-				priceEntry = prices.get(prices.size() - 1);
-				hit = false;
+				// Queue a check for the price
+				itemService.queueLookup(itemId);
 			}
 		}
 

http-service/src/main/java/net/runelite/http/service/item/ItemService.java

@@ -32,6 +32,7 @@ import java.time.Instant;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
+import java.util.concurrent.ConcurrentLinkedQueue;
 import lombok.extern.slf4j.Slf4j;
 import net.runelite.http.api.RuneLiteAPI;
 import net.runelite.http.api.item.ItemType;
@@ -40,6 +41,7 @@ import okhttp3.Request;
 import okhttp3.Response;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.beans.factory.annotation.Qualifier;
+import org.springframework.scheduling.annotation.Scheduled;
 import org.springframework.stereotype.Service;
 import org.sql2o.Connection;
 import org.sql2o.Query;
@@ -78,7 +80,10 @@ public class ItemService
 	private static final String CREATE_PRICES_FK = "ALTER TABLE `prices`\n"
 		+ "  ADD CONSTRAINT `item` FOREIGN KEY (`item`) REFERENCES `items` (`id`);";
 
+	private static final int MAX_PENDING_LOOKUPS = 512;
+
 	private final Sql2o sql2o;
+	private final ConcurrentLinkedQueue<Integer> pendingPriceLookups = new ConcurrentLinkedQueue<>();
 
 	@Autowired
 	public ItemService(@Qualifier("Runelite SQL2O") Sql2o sql2o)
@@ -339,4 +344,26 @@ public class ItemService
 			return response.body().bytes();
 		}
 	}
+
+	public void queueLookup(int itemId)
+	{
+		if (pendingPriceLookups.size() >= MAX_PENDING_LOOKUPS)
+		{
+			return;
+		}
+
+		pendingPriceLookups.add(itemId);
+	}
+
+	@Scheduled(fixedDelay = 5000)
+	public void checkPrices()
+	{
+		Integer itemId = pendingPriceLookups.poll();
+		if (itemId == null)
+		{
+			return;
+		}
+
+		fetchPrice(itemId);
+	}
 }

http-service/src/test/java/net/runelite/http/service/SpringBootWebApplicationTest.java

@@ -34,11 +34,13 @@ import org.junit.Test;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.context.annotation.Bean;
+import org.springframework.scheduling.annotation.EnableScheduling;
 import org.sql2o.Sql2o;
 import org.sql2o.converters.Converter;
 import org.sql2o.quirks.NoQuirks;
 
 @SpringBootApplication
+@EnableScheduling
 public class SpringBootWebApplicationTest
 {
 	@Bean("Runelite SQL2O")